- Self-inflating bag
In various sizes:
- Infant: 240mL
- Child: 500mL
- Adult: 1600mL
- Oxygen source
- Air inlet valve
Draws room air into the bag if the oxygen reservoir is empty and the bag is still inflating.
- One-way valves
Sit between the self-inflating bag and the:
- Gas source
Refill valve prevents reflux of gas into the reservoir instead of into the patient.
- Exhalation port Non-rebreathing valve prevents expiration into the self-inflating bag, and forces expiration through the exhalation port (or PEEP valve, if present).
- Gas source
- 15mm adaptor
For mask or airway device.
- High pressure relief valve
Pop-off valve prevents Pip rising excessively (usually at ~40-65cmH2O, depending on model).
- PEEP valve
Partially occludes exhalation port to provide PEEP. May be built-in or sold separately.
- Oxygen reservoir
Must be at least as large as the bag. Allows buffering of gas flow into the self-inflating bag (as peak flow will be less than that supplied from the oxygen source), and allows 100% O2 to be delivered provided the minute ventilation is less the O2 flow rate.
- Attach to supplemental oxygen
- Attach to mask or airway device
- Hand ventilate
- Widely available
- Requires no power
- Can deliver close to 100% oxygen
- Minimal dead space
- Pop-off valve reduces risk of barotrauma
- Highly compatible
15mm adaptor compatible with masks, LMA, ETT, and other in-line airway add-ons (ETCO2, bronchoscopic Y-piece, etc.).
- Misassembly Reusable BVM systems can occasionally have their valves inserted backwards, giving risk of barotrauma and failure of oxygen delivery.
- Less effective for spontaneous ventilation
- Delivered FiO2 may vary substantially between devices
- Requires sufficient ventilatory effort to open one-way valves
Failure will result in air entrainment rather than oxygen.
- Lower FiO2 delivered at high MV
- Easy to hyperventilate
- Unable to gauge lung compliance
Risk of barotrauma.
- Difficulty assessing delivered tidal volumes